The DNA Sequencing Core will provide members of the Rheumatic Disease Core Center with access to high-throughput DNA sequencing technology. This capability will continue to be a critical component of molecular analysis of the basis of rheumatic diseases. The Sequencing Core principally operates a newly purchased Applied Biosystems Model 3700 DNA Sequencers, and maintains computer and robotics support facilities to aid its operation; additional sequencers are maintained in operational condition to provide back up capacity and continued service in the case of equipment failure. Recent increases in automation have improved reliability and reduced per-sample costs. Sequencing generates an average of at least 700 nt of highly accurate sequence, with an additional 300-500 nt of readable sequence. We aim to return results, via a web-based computer file transfer within 2 days of sample submission. Approximately 40 members of the proposed RDCC have historically been users of the DNA Sequencing Core, and based on past experience, it is projected that they will request at least 10,000 lanes of sequencing in 2002, with an annual growth of 50% each year thereafter. While non- discounted clients are charged $10 per lane for sequencing (one template, one primer), RDCC members will be charged $5 per lane. Future plans include introduction of a shotgun sequencing service in order to provide complete sequencing of long templates, and a genotyping service.